Navigation Lines and Recommended Tracks

I have noticed that some mappers are using the seamark:type "navigation_line" and "recommended_track" to indicate fairway centrelines. This is incorrect. A fairway should be mapped as an area with the type "fairway". No centreline should be separately mapped. Very often, even a fairway need not be mapped if the channel is well marked with buoys and/or beacons.

Both Navigation Lines and Recommended Tracks must be straight lines that project to a pair of transit objects or other directional object. Therefore they should only have two nodes.